The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
Competing commercial web sites such as search engines constantly strive to differentiate from each other in order to attract users. The user base of a site has a direct bearing on advertisement revenue and hence profitability of a site. Site designers continuously monitor user opinions of web sites such as whether a particular search engine has more relevant information than another, whether a given web site is better, or whether a given web site design layout is cleaner. While an editorial team can easily perform an information relevancy analysis for search engine results, the outcome of the relevancy analysis does not necessarily track user opinion. The disparity in user opinion and relevancy is explained by features related to perception that lead to opinions like “better” and “design layout is cleaner.” Perception-related features contribute to long term user satisfaction, which affects the number of users of the site and consequently receive attention from site designers.
A user will devote only up to a fixed amount of time to the perception of a given page. If a user is unable to find what he or she wants within a given time budget, then the user will move on from the page. This indicates that the efficiency with which a user is able to absorb information from a given page contributes to user satisfaction.
Publishers, in a drive to increase user satisfaction, attempt to understand how various design features affect user perception of a page. Publishers also want to mitigate the risk associated with introducing new page designs. Publishers use a number of approaches to mitigate risk, such as collecting live statistics, conducting surveys, running usability studies, performing eye-tracking studies. However, none of the approaches attempt to measure how efficiently users process information on a page. In other words, none of the approaches measures the cognitive efficiency of a page.
User requirements for web pages depend on the primary purpose of a given page. Web pages can be divided into two classes: informational and navigational. Informational pages are intended to be the end point of a search. For example, if a user searches for information regarding a certain high blood pressure drug, and arrives at a page that contains the needed information, then the user will stay at the page for an extended period of time and absorb the information. A navigational page is built with the primary purpose to redirect the user to his intended destination. A typical example of a navigational page is a results page generated by a search engine.
A common metric for informational and navigational pages is how much time a user spends at each. A designer of an informational page strives to maximize the time a user spends on the page. Prolonged time indicates that the page's content is of interest. However, for navigational pages, time spent on the page should be minimized, so that the user is able to move to the intended destination as quickly as possible.
Search engine publishers or designers collect various live data, such as query logs, mouse click data, click-through rate, and data about how long users stay on a particular page. Publishers and designers collect this data in order to gain insight into user behavior and into factors contributing to user satisfaction. Click-through rate, or “CTR,” is a measure of online advertisement effectiveness.
CTR is a ratio of (a) the number of clicked-on advertisements to (b) the number of advertisements that were shown. CTR is directly tied to the advertisement revenue. CTR can only quantify performance of a particular design at an aggregate level and yields no information on what bearing each element of the design has on the user. Query logs, correlated with mouse clicks, can be used to examine the effectiveness of information presentation; however, query logs provide limited insight because users submitting the queries are not readily identifiable. In the instances where users are identifiable, users most often are unable to articulate their exact thought process for a particular mouse click. A mouse click on a search engine page is a result of a number of decisions made by the user, such as a decision about whether the abstract was meaningful or whether the title was interesting.
Structured experiments have also been used to study and characterize the impact of page design on perception. Some common approaches include asking users to detail their thought processes as they are using the search engine interface. Another approach involves using surveys. Most recently, eye-tracking studies have been conducted. However, having a study participant describe his thought process while looking at a page heavily affects the experiment. Typically, the time that passes before a user's first click in a search page is in the order of seconds. Vocalization inevitably slows down the study participant's decision-making process, which allows the study participant to notice extra visual cues. Administering surveys to a user after the user has navigated through several pages also presents problems, such as lack of user motivation and lack of user memory. If users are provided items for which to search, then the users are often unmotivated and less likely to spend time performing the search. As a result, searches are finished in a shorter time frame. User memory becomes an issue because if the user makes a rapid series of decisions before clicking on a link, then the user will not remember some of the decisions. Consequently, the user's decisions become impossible to capture in a survey.
As is mentioned above, eye tracking is a technique that is used to study how a user perceives a given page. A typical, non-invasive eye-tracking system uses an infrared light source and a special video-recording device to measure reflections that are present on the eye. This measurement is performed to gauge the eye's precise position. The human eye is structured in a way such that objects are seen in a very small area of a focus point. Objects outside of the focus point appear to the observer as though the observer were looking through a frosted glass; the detail is filled in by the brain. The human eye is able to detect motion and certain patterns in the eye's periphery. Studies of perception based on eye tracking use the small focus point and operate on the assumption that what a user is seeing, the user is also thinking about.
There are several types of data that may be derived from eye-tracking studies, gaze plots, mouse click locations, and fixation data which is transformed into page heat maps. Eye-tracking systems record the position of a user's focus point as the user is looking at pages. The eye-tracking system correlates the focus point information with what the user sees on a computer monitor and mouse movement. The eye-tracking system is integrated with the computer's Internet browser. The eye-tracking system is able to determine which portion of the page at which a user has been looking even if the user scrolled up or down the page. That way, the eye-tracking data can be combined with respect to a common reference point.
In order to perceive a web page in its entirety, users scan the page using rapid eye movements, thereby moving the focus point rapidly. The movement of the focus point is recorded by the eye-tracking system. The recorded path is called a gaze plot. As a user is scanning a page, the user's eyes tend to seek out the most interesting part of the visual input. The eyes focus on the most dynamic part, while the rest of the picture is filled in by the brain. The eyes, when changing the position of the focus point, enter a ballistic state. In transit, or ballistic state, the eyes are not capturing any information. Information capture restarts once the focus point stops moving. The complete movement is captured by the eye-tracking system. When a focus point remains stationary for a predetermined period of time, the eyes are said to have fixated on a point. The predetermined period of time is called a fixation. If the focus point remains stationary for multiple predetermined periods of time, then the focus point remains stationary for multiple fixations. A fixation is a finite element of time that one spends looking at a single point. For example, if a fixation were assigned a value of 1/16 of a second and if a person were to look at a point for ⅛ of a second, then the person would have looked at the point for a duration of 2 fixations
A page heat map is a visualization of all eye fixations for a page aggregated across multiple people. The time during which the eye is stationary is counted in finite increments or fixations. In a heat map, a different color is assigned to a certain part of the page based on the number of fixations. A graduated color scale can be used to visualize the fixations. A color scale can be arbitrarily assigned, for example with colors ranging from blue to red. Areas of red indicate a higher number of fixations received by the area, and imply that people spent a longer time looking at the area. Areas of blue indicate that the area received few fixations, and correspondingly fewer people spent time looking at the areas of blue.
There are two possible extremes for heat maps. At one extreme, a user's fixations can be spread uniformly over the entirety of the page, which indicates that the page was seen but not much was specifically noticed. At the other extreme is a web page that contains areas of highly concentrated fixations, while other portions of the page have no fixations at all. In that case, content on the page was noticed in the areas of high concentration of fixations, but content was not even seen in other portions of the page.
A large advantage of eye-tracking systems is that a user is able to search naturally, without slowing down. The user is able to make decisions without talking. At the end of a search session, the eye tracker produces a time-correlated set of data which includes a video log, the pages visited, mouse clicks, and eye-tracking data. Using the combined data, a study participant can be questioned to gain insight into his thought process.
All of the current approaches provide limited information. Currently, data generated by eye-tracking systems is used to obtain qualitative data regarding specific design elements. The eye-tracking data is used to answer questions such as “where did people look?” and “how did the gaze progress across the page?” The questions provide a localized view of the page's layout design and cannot be used to predict accurately behavior of larger groups of users, specifically (a) how a users will perceive a web page, (b) overall user satisfaction, or (c) the possible CTR. Live data, such as CTR along with raw revenue, can provide a much coarser quantitative metric of design performance but does not provide concrete data on how a user perceives a given page's layout design, and does not yield information about the effect of individual design elements. There exists a need for an automatically derivable metric that measures how users perceive web pages.